Resilient yielding material



June 28, 1938. A. A. M CORMACK 2,122,373

v RESILIENT YIELDING MATERIAL Filed Oct. :50, 1935 lww INVEN 1 ORATTORNEYS Patente utime 28, 1938 STATES PATENT orrica nEsmmN'r mmmoMATERIAL v Alex A. McCormack, Dayton, Ohio, assignor to General MotorsCorporation, Dayton, Ohio, a corporation of Delaware Application Qctober30, 1935, Serial No. 47,516

2 Claims. (Cl. 106-22) This invention relates to refrigerating app tusand more particularly to a resilient yielding material for acting as aseal between metal parts in a refrigerating system.

In refrigerating systems it is necessary at many relatively short timecauses it to become unsetisfactory for most sealing purposes andordinarily permits the seal to leak after a period of time.

It has been proposed to use a polymer of chloro- 2-butadiene-L3 as aseal between metal parts of refrigerating systems in the place of rubberor other elastic materials which might be used. However, I find thatordinary compounds containing this polymer are not well suited forrefrigerating systems because they tend to swell or increase indimensions considerably when in contact with the refrigerant and thelubricant in the refrigerating system and because they tend todisintegrate or partially dissolve in the presence of a refrigerant andlubricant.

It is an object of my invention to provide an improved yielding,resilient, elastic rubber-like material containing no rubber which willsatisfactorily and permanently provide a resilient elastic seal betweenmetal parts of a refrigerating system.

It is a more specific object of my invention to provide an improvedyielding elastic rubberlike material containing no rubber which willsatisfactorily and permanently provide a seal between metal parts of arefrigerating system containing a halo derivative of a hydrocarbon andparticularly systems containing chloro iiuoro derivatives of analiphatic hydrocarbon such as difluorodichloromethane andtetrafiuorodichloroethane.

Further objects and advantages of the present invention will, beapparent from the following description, reference being had to theaccompanying drawing, wherein a preferred form of the present inventionvis clearly shown.

In the drawing:

Fig. 1 is a view of the refrigerating system, partly diagrammatic,illustrating one form of seal embodying my invention; and

Fig. 2 is an enlarged sectional view of a shaft portion of a refrigerantcompressor illustrating another seal embodying my invention.

Briefly, as a resilient seal between metal parts in a refrigeratingsystem, containing a halo derivative of a hydrocarbon, I employ acompound containing the following substances in parts by volume:

Parts Polymer of chloro-2-butadiene-1,3 100 Light calcined magnesiumoxide 10 Zinc oxide :10' FF wood rosin 2 Channel black (carbon) 29Referring now more particularly to the drawing, there is shown arefrigerating system generally designated by the reference charactercontaining a refrigerant such as difiuorodichloromethane ortetrafluorodichloroethane and a lubricant such as a mineral baserefrigerator oil 22 shown in the bottom of the crank case of acompressor 24. The compressor 24 is driven through its drive shaft 26 byan electric motor 28 for compressing the refrigerant and for forwardingthe compressed refrigerant to a condenser 30 where the compressedrefrigerant is liquefied and forwarded under the control of a suitableautomatic valve 32 to an evaporating means 34 located within anenclosure 36 containing a medium to be cooled. Within the evaporatingmeans 34 the refrigerant evaporates under a reduced pressure and isreturned to the crank case of the compressor by conduit means.

The drive shaft to the compressor extends through the wall 38 of thecompressor which wall is provided with a bearing 40 for supporting oneend of the drive shaft. This wall is also provided with a hollow boss 42for receiving a shaft seal which prevents the escape of refrigerant andlubricant from the crank case of the compressor through the openingprovided for the drive shaft. This seal also prevents the ingress of airinto the crank case. This boss 42 is provided with an end plate 46,fastened to the boss by screws 48.

the reduced portion 54 of the drive shaft 26.

. frigerant to this space. It will thus be seen that 2 This end plate isprovided with an annular sealing surface 50 with which the shaft sealcooperates to form a relatively rotating fluid tight Joint toprevent theescape of refrigerant and lubricant between the sealing ring 52 and thereduced por-' tion 54 of the drive shaft 26 so as to form a fluid tightseal between the sealing ring 52 and the reduced portion 54 of the driveshaft 25. This is performed by a cup-shaped annular member 58 whichsurrounds the reduced portion 54 of the drive shaft 26 and holds oneface and the adjacent portion of the outer periphery of the wedge-shapedrubberlike sealing ring 55 and also surrounds and rides upon the outerperiphery of the sealing ring 52. This cup-shaped annular member 58 hasan integral flange which receives one end of a compression type coilspring Gil. This coil spring 60 provides the force necessary for thecup-shaped member to wedge the resilient elastic rubberlike ring tightlybetween the sealing ring 52 and the reduced portion 54 of the driveshaft 25 as well as to provide sufficient force to hold the sealing ring52 in sufliciently tight sealing engagement with the sealing surface 50upon the end plate 56.

The other end of the compression spring 60 is held by a disc or washer62 which presses against a shoulder 64 formed between the reducedportion 54 and the bearing portion of the drive shaft 26. The wedging ofthe rubberlike wedgeshaped ring 55 between the sealing ring 52 andcauses the entire shaft seal to rotate with the shaft 26. This causesrelative rotation between the sealing ring 52 and the sealing surface50.

In order to lubricate these relatively rotating sealing surfaces, I haveprovided a passage for oil for lubricating the space containing theshaft seal. ,While this passage 66 is intended for oil, it also permitsthe free access of rethe rubberlike wedge-shaped ring 56 is exposed tothe action of both refrigerant and lubricant. It is well known thatrubber deteriorates in the presence of oil and is also attacked by theordinary refrigerants. I have also found that ordinary compounds ofrubber substitutes also are unsatisfactory for such use in arefrigerating system since most of them are subject to considerableswelling which is sufllcient to distort the ring 55 and to prevent itsproper action. v

I have, therefore, provided an improved ring 55 of a molded compositionwhich will meet the conditions required for this service. Thiscomposition contains no rubber and will withstand immersion in oil atrelatively high temperatures without disintegrating or increasing thedimenof between 65 and '15 according tothe' Shore scleroscope system ofmeasurement. It Is comcassava pounded according to the following formulain parts by volume:

Parts by g Specific y volvolume me gravity Pol er oIehloro-2-butadIene-l. 3-. 100 66. 2 i. 24

Li t calcined magnesium oxide 10 6. 6 2. 4 Zinc oxide i0 6. 6 5. 57

FF wood rosin 2 1. 3 l. 4 Channel black.. 29 19. 2 l. 75

The channel black is a grade of carbon black. However, ordinary carbonblack or lamp black or even graphite may be substituted in the sameproportions for the channel black with very little or no changeinproperties. This'substance may be used for various types of gasketsand washers used'in refrigerating systems containing halo derivatives ofhydrocarbon and other uses. In the place of FF wood rosin, anyequivalent resin ,may be used.

In Fig. 2, I have shown another form of seal having this samecomposition. In this modification, there is shown a wall I25 of arefrigerant compressor, preferably containing a lubricant and a haloderivative of a hydrocarbon as a refrigerant such asdifluorodichloromethane or tetrafluorodichloroethane. This wall Iwisprovided with a bearing I22 which supports one end of the compressordrive shaft I24 provided with a reduced portion I28 forming a shoulder52s upon the drive shaft. Surrounding this reduced portion of the driveshaft is a bellows type of shaft seal which is enclosed within a hollowboss I provided with an outer ring I32 which clamps the fixed end plateI84 of the shaft seal to the wall of the compressor. This end platesupports one end of a flexible metal bellows I35 which surrounds thereduced portion I25 of the drive shaft I24. The other end of thisbellows is provided with a sealing ring I35 of a good wearing materialwhich is provided with a flange -I4Il which in turn supports one end ofthe compression spring I42 extending between the flange I45 and thefixed end plate I24 for resiliently urging the sealing ring I28 towardthe shoulder ever, I have found that it is dimcult to provide a.v

hard, smooth, perfectly flat, concentric, wearing surface upon theshoulders of the shaft and I have therefore proposed a separate sealingring I44 which is resiliently held in placebya resilient elasticrubberlike sealing ring I48 preferably of the some molded composition asspecifled in detail above for the improved sealing ring 58. I find thatsuch a compound foruse in connection with halide refrigerants issuperior to any similar compound heretofore used. This rubberlikesealing ring extends around three sides of the annular metal ring I44and fits tightly between the rings I44 and the reduced portion I25 ofthe drive shaft I24.

The metal seal ring I44 is preferably hardened and ground so that a prfectly smooth face is provided-for mating with sealing surface I of thering III. This seal likewise is exposed to the as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope oi the claims whichfollow.

t is claimed is as follows:

i. A resilient seal for refrigerating systems comprising a substancecontaining ingredients about in the following proportions by volume:

Per cent Polymer of chloro-2-butadiene-L3 68.2 cesium oxide 6.6 Zincmflde 6.6 Wood xosh 1.3 Car I L 19.2

2. A resilient material comprising a substance containing ingredientsabout in the following proportions by volume:

Ports Polymer oi chloro-Z-butadiene-IB 100 Magnesium oxide 16 Zinc oxide10 Wood rosin 2 Carbon 29 A. MccoRMAcKl

